In medium bowl, combine eggs, milk and salt; beat with wire whisk until blended.
In large bowl combine asparagus, artichokes, mushrooms and Spam.

In 10-inch non-stick skillet over medium heat, melt 1 teaspoon butter. Add one-fourth of egg mixture; just as it begins to set, use a wooden spoon to scrape the egg from the bottom (working like you are scrambling eggs). Stop scraping just before the eggs are totally cooked. Sprinkle one-fourth of Cheddar cheese and one-fourth vegetable mixture down the center of the omelet. Use a rubber spatula to carefully fold the egg over on itself. (The bottom of omelet should have a light brown crust.) Slide omelet onto serving plate.

Repeat with remaining eggs and mixture to make 4 omelets in all. Season with salt and pepper to taste. Garnish with chopped parsley.